//
// (C) Copyright 2009 Irantha Suwandarathna (irantha@gmail.com)
// All rights reserved.
//

/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use _in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions _in binary form must reproduce the above copyright notice, 
 * this list of conditions and the following disclaimer _in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


using System;
using System.Collections;
using System.Text;


namespace EffiProzDB
{
    /**
     * Implementation of a bit map of any size, together with static methods to
     * manipulate int values as bit maps.
     *
    * @author fredt@users
    * @version 1.8.0
    * @since 1.8.0
    */
    public class BitMap
    {

        int defaultCapacity;
        int capacity;
        int[] map;

        public BitMap(int initialCapacity)
        {

            int words = initialCapacity / 32;

            if (initialCapacity % 32 != 0)
            {
                words++;
            }

            defaultCapacity = capacity = words * 32;
            map = new int[words];
        }

        /**
         * Resets to blank with original capacity
         */
        public void reset()
        {
            map = new int[defaultCapacity / 32];
            capacity = defaultCapacity;
        }

        /**
         * Sets pos and returns old value
         */
        public int set(int pos) {

        while (pos >= capacity) {
            doubleCapacity();
        }

        int windex = pos >> 5;
        int mask   =(int)((uint) 0x80000000 >> (pos & 0x1F));
        int word   = map[windex];
        int result = (word & mask) == 0 ? 0
                                        : 1;

        map[windex] = (word | mask);

        return result;
    }

        /**
         * Unsets pos and returns old value
         */
        public int unset(int pos) {

        if (pos >= capacity) {
            return 0;
        }

        int windex = pos >> 5;
        int mask   = (int)((uint)0x80000000 >> (pos & 0x1F));
        int word   = map[windex];
        int result = (word & mask) == 0 ? 0
                                        : 1;

        mask        = ~mask;
        map[windex] = (word & mask);

        return result;
    }

        public int get(int pos)
        {

            while (pos >= capacity)
            {
                doubleCapacity();
            }

            int windex = pos >> 5;
            int mask = (int)(((uint)0x80000000) >> (pos & 0x1F));
            int word = map[windex];

            return (word & mask) == 0 ? 0
                                      : 1;
        }

        public static int set(int map, int pos)
        {

            int mask = (int)(((uint)0x80000000) >> pos);

            return (map | mask);
        }

        public static int unset(int map, int pos)
        {

            int mask = (int)(((uint)0x80000000) >> pos);

            mask = ~mask;

            return (map & mask);
        }

        public static bool isSet(int map, int pos)
        {

            int mask = (int)(((uint)0x80000000) >> pos);

            return (map & mask) == 0 ? false
                                     : true;
        }

        private void doubleCapacity()
        {

            int[] newmap = new int[map.Length * 2];

            capacity *= 2;

            Array.Copy(map, 0, newmap, 0, map.Length);

            map = newmap;
        }
    }
}
